Stabilized magnesium hydroxide slurry

ABSTRACT

A method for producing a stabilized magnesium hydroxide slurry comprising physically deflocculating the magnesium hydroxide solids in a starting slurry to produce a stabilized magnesium hydroxide slurry. Depending on the chloride level of the starting slurry, a cationic polymer may be added to the slurry. Optionally a thickening agent may be added to the deflocculated slurry. Also disclosed is a stabilized magnesium hydroxide slurry produced by the method which may be transported and stored without substantial agglomeration of the magnesium hydroxide solids.

This is a continuation of application Ser. No. 08/517,323 filed Aug. 21,1995. Now abandoned, which was a continuation of 08/046,283, filed Apr.15,1993, now U.S. Pat. No. 5,514,351.

FIELD OF THE INVENTION

The present invention relates to a stabilized magnesium hydroxide slurrythat may be transported, pumped and/or stored without substantialagglomeration. The present invention also relates to a method forproducing the stabilized magnesium hydroxide slurry.

BACKGROUND OF THE INVENTION

Magnesium hydroxide, Mg(OH)₂, is widely used in industry as aneutralizing agent, as a gas absorber, in waste water treatment, inpower plant applications and in other utilities. Magnesium hydroxide hasalso recently replaced sodium hydroxide in many applications due to theincreased price of sodium hydroxide and to shortages of sodiumhydroxide.

Magnesium hydroxide, may be derived from three basic sources: seawater,well brines and magnesite ore. In a typical process a magnesiumhydroxide slurry is produced from the chemical reaction of dolime(CaOMgO) and well brine. The well brine comprises primarily calciumchloride but also includes magnesium chloride. The chemical reaction ofdolime and well brine produces a slurry of magnesium hydroxide in achloride containing liquor. The slurry is then further processed toreduce the chloride level, and concentrated to approximately 40-55%magnesium hydroxide solids. If desired the magnesium hydroxide slurrymay be further processed in various types of furnaces to produce amagnesium oxide product.

The viscosity of a magnesium hydroxide slurry increases with increasingmagnesium hydroxide solids loading (concentration) and does sodramatically as the loading exceeds 45%. Under normal conditions the40-55% solids magnesium hydroxide slurry will have a relatively highviscosity, possibly between 3000 and 4000 centipoise. In many heretoforeknown magnesium hydroxide slurries, if agitation of the slurry isabsent, the solids tend to settle and agglomerate. The settling andagglomeration results in an extremely hard mass which, after a period oftime, is extremely difficult, if not impossible, to re-suspend.

A magnesium hydroxide slurry having these characteristics could not beshipped for long distances, or stored for more than a short time withoutagitation without the slurry ceasing to be in pumpable form.Furthermore, even if a portion of the transported slurry could betransferred from the transport vehicle, generally a truck or rail car,the hard mass of agglomerated slurry ("heel") remaining in the vehiclewould could not easily be resuspended and therefore would need to bemanually removed from the transport vessel by shoveling and/or scraping.Additionally, the portion of the slurry that could be transferred wouldneed to be maintained under substantially constant agitation to preventagglomeration of the solids.

For these and other reasons, it would be advantageous to have a stable,high solids content, magnesium hydroxide slurry that may be transported,pumped and/or stored without substantial solids agglomeration. It wouldalso be advantageous to have a stable, high solids content, magnesiumhydroxide slurry that would permit any solids that did agglomerate to beeasily resuspended. Further, it would be advantageous to have a stable,high solids content, magnesium hydroxide slurry that could betransported in trucks or rail cars for a period of up to 14 days andevacuated from the truck or rail car leaving only a minimal "heel" ofagglomerated solids.

The present invention achieves these advantages as well as otheradvantages that will be apparent from the following description.

SUMMARY OF THE INVENTION

The present invention is directed to a method for producing a stablemagnesium hydroxide slurry, and the slurry produced by the method.

According to the method of the present invention, a magnesium hydroxideslurry, produced by conventional methods such as from well brines,having the desired solids content, generally between 50 and 65% solids,by weight, is subjected to a physical deflocculation step to produce astabilized magnesium hydroxide slurry. Depending on the chloride levelof the starting magnesium hydroxide slurry, the method may also includetreating the slurry with a cationic polymer to lower the viscosity ofthe slurry to a point which enables the physical deflocculation step toproceed to substantial completion. In a preferred method of the presentinvention, a thickening agent is added to the slurry during or after thephysical deflocculation step.

Physical deflocculation refers to a process wherein the magnesiumhydroxide solid particles are subjected to mechanical forces which breakup small loose agglomerations of the particles.

The method of the present invention advantageously produces a stabilizedmagnesium hydroxide slurry that can have a magnesium hydroxide solidscontent of up to 65%, by weight, and can be shipped long distances forperiods of 7-14 days without agitation and arrive in a state wherein theslurry can be removed from the transporter by pumping, pressure orgravity without leaving a significant "heel" in the transport container.

The method of the present invention also advantageously produces astabilized magnesium hydroxide slurry that will remain stable andsubstantially free of agglomerated magnesium hydroxide solids for anindefinite period of time with agitation, or for at least 30 dayswithout agitation.

The method of the present invention further advantageously produces astabilized magnesium hydroxide slurry that will not plug up transferlines and/or metering pumps.

The stabilized magnesium hydroxide slurry of the present invention ischaracterized by having a magnesium hydroxide solids content of 50 to65%, by weight wherein substantially all of the solids aredeflocculated. Preferably the stabilized magnesium hydroxide slurry ofthe present invention also has one or more of the following properties:a viscosity of 50-1000 centipoise (cps); a density of 1.4-1.6grams/cubic centimeter (g/cc); a mean particle size of the magnesiumhydroxide solids of 1.7-5.0 microns, preferably 34 microns; and achloride level of 0.30-0.75% by weight on a MgO basis, preferably0.35-0.60 by weight on a MgO basis. The stabilized magnesium hydroxideslurry may also include 1 to 5000 parts per million (ppm) of a cationicpolymer. A preferred stabilized magnesium hydroxide slurry of thepresent invention additionally includes 1 to 100 ppm of a thickeningagent.

The stabilized magnesium hydroxide slurry of the present invention hasthe aforementioned advantages as well as other advantages that will beapparent to those of ordinary skill in the art from the following moredetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a possible embodiment of the method of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The method of the present invention for producing a stabilized magnesiumhydroxide slurry comprises the following steps:

determining the chloride level of a starting magnesium hydroxide slurry;

adding between 0 and 5000 parts per million ("ppm"), of a cationicpolymer to the starting slurry; wherein if the chloride level of thestarting slurry is less than or equal to 0.42%, by weight on a MgObasis, 0 ppm of the cationic polymer is added to the starting slurry; ifthe chloride level of the starting slurry is 0.43-0.52%, by weight on aMgO basis, 1000 ppm of the cationic polymer are added to the startingslurry; if the chloride level of the starting slurry is 0.53-0.65%, byweight on a MgO basis, 2500 ppm of the cationic polymer are added to thestarting slurry; and if the chloride level of the starting slurry isgreater than or equal to 0.66%, by weight on a MgO basis, 3500-5000 ppmof the cationic polymer are added to the starting slurry;

physically deflocculating the magnesium hydroxide solids in the slurry,without homogenizing the slurry, to produce a stabilized magnesiumhydroxide slurry. In a preferred embodiment of the method of the presentinvention, the method includes the additional step of adding athickening agent in an amount of 1-100 ppm to the slurry to raise theviscosity of the slurry to a desired level.

The stabilized magnesium hydroxide slurry of the present inventioncomprises:

50-65%, by weight, deflocculated magnesium hydroxide solids; wherein theslurry will remain substantially free of agglomerated magnesiumhydroxide solids for at least 30 days. Preferably the stabilizedmagnesium hydroxide slurry of the present invention also has one or moreof the following properties: a viscosity of 50-1000 cps; a density of1.4-1.6 g/cc; a mean particle size of the magnesium hydroxide solids of1.7-5.0 microns, preferably 3-4 microns; and a chloride level of0.30-0.75% by weight on a MgO basis, preferably 0.3-50.60 by weight on aMgO basis. The stabilized magnesium hydroxide slurry may also include upto 5000 parts per million (ppm) of a cationic polymer, wherein if thechloride level of the slurry is less than or equal to 0.42%, by weighton a MgO basis, the slurry includes 0 ppm of the cationic polymer; ifthe chloride level of the starting slurry is 0.43-0.52%, by weight on aMgO basis, the slurry may include 1000 ppm of the cationic polymer; ifthe chloride level of the starting slurry is 0.53-0.65%, by weight on aMgO basis, the slurry may include 2500 ppm of the cationic polymer; andif the chloride level of the starting slurry is greater than or equal to0.66%, by weight on a MgO basis, the slurry may include 3500-5000 ppm ofthe cationic polymer. A preferred stabilized magnesium hydroxide slurryof the present invention additionally includes 1 to 100 ppm of athickening agent which raises the viscosity of the slurry to a desiredlevel.

The chloride level of the starting magnesium hydroxide slurry may bedetermined in any manner known to those of ordinary skill in the artincluding X-Ray Flouresence Spectrometry. The %, by weight on a MgObasis refers to the %, by weight chloride in comparison to thecalculated %, by weight of MgO in the slurry solids.

The particle size of the magnesium hydroxide solides may be determinedin any manner known to those of ordinary skill in the art, includingX-Ray Monitored Sedimentation.

Suitable cationic polymers for use in the method and stabilizedmagnesium hydroxide slurry of the present invention include but are notlimited to: Holly Fix 1, a cyano-guanidine polymeric resin manufacturedand sold by Holly Oak Chemical, Inc., of Fountain Inn, S.C. and having aboiling point of 212° F. and a specific gravity of 1.186@25° C.Additional suitable cationic polymers are known to those of ordinaryskill in the art. While not wishing to be bound by any particulartheory, it is believed that the cationic polymer assists in thedeflocculation of higher chloride content starting magnesium hydroxideslurries by reducing the viscosity of the starting slurry to a pointwhere the slurry may be physically deflocculated.

The physical deflocculation of the magnesium hydroxide solids in thestarting magnesium hydroxide slurry may be accomplished by any meansknown to those of ordinary skill in the art, provided that minimalhomogenization of the slurry occurs during the physical deflocculationstep. Preferably, the slurry is physically deflocculated using anhomogenizer wherein the operating conditions are controlled to minimizehomogenization of the slurry but deflocculate substantially all of themagnesium hydroxide solids. A preferred homogenizer is an APV GaulinHomogenizer, manufactured and sold by APV Gaulin, Wilmington, Mass. Inorder to physically deflocculate the magnesium hydroxide solids, theslurry is passed through the APV Gaulin Homogenizer, generally at apressure of 1000-8000 pounds per square inch (psi). The slurry may bepassed through the APV Gaulin Homogenizer 1-10 times. The term "pass"refers to a complete turnover of the slurry in the vessel. In thepreferred method of operation, the slurry is passed through the APVGaulin Homogenizer 3 times at approximately 2500 psi. An alternativemethod of operation is to recycle the slurry through the APV GaulinHomogenizer instead of using discrete passes. A preferred recyclingtime, at approximately 2500 psi, is equivalent to 3.25 passes.

Suitable thickening agents for use in the method and stabilizedmagnesium hydroxide slurry of the present invention include, but are notlimited to: CMC (carboxymethylcellulose), guar gum and xanthum gum.

The process and stabilized magnesium hydroxide slurry of the presentinvention will be described in more detail with reference to FIG. 1.Although, FIG. 1 depicts a particular embodiment of the process of thepresent invention, it should be understood that the process of thepresent invention is not limited to the particular embodiment depictedin FIG. 1.

Referring to FIG. 1, a starting magnesium hydroxide slurry having asolids content of approximately 50-60%, produced by a conventionalprocess such as from well brines, is transferred from a drum filterunit, 2, utilized in producing the starting slurry, to slurry storagetank, 4. Slurry storage tank 4 contains agitation means 5, to minimizethe agglomeration of the magnesium hydroxide solids in the startingslurry.

The chloride content of the starting slurry may be determined in theslurry storage tank, 4. The starting slurry is pumped from slurrystorage tank 4, to process tanks 8 and 10. Optionally, the startingslurry may be pumped through drum or disc filter 6, prior to enteringprocess tanks 8 and 10. Drum or disc filter 6, may be utilized if it isdesired to further concentrate the starting slurry to raise the level ofmagnesium hydroxide solids.

Depending on the chloride content of the starting slurry a cationicpolymer may be added to the slurry while the slurry is being pumped fromstorage tank 4 to process tanks 8 and 10. The addition of cationicpolymer to the slurry is shown by box 7, in FIG. 1. If the chloridelevel of the starting slurry is less than or equal to 0.42%, by weighton a MgO basis, 0 ppm of the cationic polymer is added to the startingslurry; if the chloride level of the starting slurry is 0.43-0.52%, byweight on a MgO basis, 1000 ppm of the cationic polymer are added to thestarting slurry; if the chloride level of the starting slurry is0.53-0.65%, by weight on a MgO basis, 2500 ppm of the cationic polymerare added to the starting slurry; and if the chloride level of thestarting slurry is greater than or equal to 0.66%, by weight on a MgObasis, 3500-5000 ppm of the cationic polymer are added to the startingslurry. The cationic polymer is evenly distributed throughout thestarting slurry in process tanks 8 and 10 and during passes through thehomogenizer.

From the process tanks 8 and 10 the slurry is pumped through homogenizer12, which is preferably a APV Gaulin Homogenizer, manufactured and soldby APV Gaulin of Wilmington, Mass. The homogenizer 12, deflocculates themagnesium hydroxide solids in the slurry. The operating conditions ofthe homogenizer, and the number of times the slurry is passed throughthe homogenizer, should be sufficient to deflocculate substantially allof the magnesium hydroxide solids in the slurry. As described above, theslurry is passed through the APV Gaulin Homogenizer, generally at apressure of 1000-8000 pounds per square inch (psi). The slurry may bepassed through the APV Gaulin Homogenizer 12 and back into process tanks8 and 10, one to ten times. In the preferred method of operation, theslurry is passed through the APV Gaulin Homogenizer 3 times atapproximately 2500 psi. An alternative method of operation is to recyclethe slurry through the APV Gaulin Homogenizer instead of using discretepasses. A preferred recycling time, at approximately 2500 psi, isequivalent to 3.25 passes.

Optionally, a thickening agent, such as CMC may be added to the slurryas the slurry is being passed through the homogenizer. The addition of athickening agent to the slurry is shown by box 14 in FIG. 1. The amountof thickening agent added to the slurry is generally between 1 and 100ppm, depending on the viscosity desired in the final stabilizedmagnesium hydroxide slurry.

After deflocculation has been completed, the stabilized magnesiumhydroxide slurry is transferred from the homogenizer to final productstorage tank 16. The final product storage tank 16 may contain means foragitating, 17, however such means are not necessary to keep thestabilized magnesium hydroxide slurry from settling. From storage tank17 the stabilized magnesium hydroxide slurry of the present inventionmay be transferred to trucks or rail cars for transport

The process described above, and depicted in FIG. 1, may be utilized toproduce a stable magnesium hydroxide slurry having a solids content of50 to 65%, by weight that will remain substantially free of agglomeratedsolids for at least 30 days. The slurry may also be characterized by oneor more of the following characteristics: a viscosity of 50-1000 cps, adensity of 1.4-1.6 g/cc, and a mean particle size of the magnesiumhydroxide solids of 1.7-5.0 microns, preferably 34 microns; and achloride level of 0.30-0.75% by weight on a MgO basis, preferably0.35-0.60 by weight on a MgO basis; wherein substantially all of themagnesium hydroxide solids are deflocculated. The stable magnesiumhydroxide slurry will remain substantially solid agglomerate freewithout agitation during transport. After a transportation period of upto 14 days the slurry will arrive at its final destination in a statewherein the slurry may be removed from the transport vessel by pumping,pressure or gravity without leaving a significant "heel" in thecontainer. After transfer to a storage tank at the final destination,the stable magnesium hydroxide slurry will remain stable for up to 30days without agitation, and remain stable indefinitely with agitation.

The following example will further illustrate the process and stabilizedmagnesium hydroxide slurry of the present invention.

EXAMPLE

This example illustrates the production of a stabilized magnesiumhydroxide slurry of the present invention utilizing the process of thepresent invention.

A starting magnesium hydroxide slurry was produced by the chemicalreaction of dolime and well brine. The dolime was obtained fromdolomitic limestone which was qurried, crushed and calcined in kilns toproduce dolime as follows:

    MgCO.sub.3 . CaCO.sub.3 →MgO . CaO+CO.sub.2.

The dolime was reacted with well brine to produce a magnesium hydroxideslurry as follows:

    MgO . CaO+H.sub.2 O→MgO+Ca(OH).sub.2

    Ca(OH).sub.2 +MgCl.sub.2 →Mg(OH).sub.2 +CaCl.sub.2

    MgO+H.sub.2 O→Mg(OH).sub.2.

The magnesium hydroxide slurry which was at this stage in an enrichedcalcium chloride liquor was thickened/settled, washed relatively free ofchlorides, further concentrated to approximately 56%, by weight, solidsand transferred to a storage vessel. At this stage the viscosity of theslurry was approximately 2000 centipoise. The magnesium hydroxide slurrythus produced, formed the starting slurry for the method of the presentinvention.

The chloride concentration of the starting slurry was determined byX-Ray Flouresence Spectrometry to be 0.48%, by weight on a MgO basis.Based on this chloride level, 1000 ppm of Holly Fix 1 cationic polymerwere added to the starting slurry as the slurry was pumped from thestorage vessel into process vessels. From the process vessels, themagnesium hydroxide solids in the cationic polymer containing slurrywere deflocculated using an APV Gaulin homogenizer at 2500 psi pressure.The slurry was passed from the process vessels through the APV Gaulinhomogenizer three times. While the slurry was being passed through thehomogenizer, 10 ppm of carboxymethylcellulose was added to the slurry.

After the final pass through the homogenizer, the stabilized magnesiumhydroxide slurry thus formed was transferred to a storage vessel. Thefinal stabilized magnesium hydroxide slurry comprised 56%, by weight,deflocculated magnesium hydroxide solids, 1000 ppm cationic polymer and10 ppm CMC and had a viscosity of 150 centipoise and a density of 1.48g/cc. The mean particle size of the magnesium hydroxide solids in thestabilized magnesium hydroxide slurry was 3.48 microns as determined byX-Ray Monitored Sedimentation using a MicroMeritics Model 5100Sedigraph.

The stabilized magnesium hydroxide slurry could be transferred to railcars, which may be fitted with an air sparger system, and transportedfor up to 14 days without agitation. After arriving at its finaldestination, the stabilized magnesium hydroxide slurry could be removedfrom the rail cars by pumping. If any settling has occurred the railcars may be sparged prior to pumping. After the stabilized magnesiumhydroxide slurry is pumped out the rail cars will be substantially freeof agglomerated magnesium hydroxide solids ("heel").

After transport, the stabilized magnesium hydroxide slurry could bestored in a storage vessel wherein it will remain substantiallyagglomeration free, without agitation, for 30 days.

We claim:
 1. A method for producing a stable magnesium hydroxide slurrycomprising:providing a starting magnesium hydroxide slurry includingloose agglomerations of magnesium hydroxide solids, said slurry having achloride content of 0.30-0.42%, by weight on an MgO basis, and having aviscosity which enables substantially all of the magnesium hydroxidesolids in the slurry to be physically deflocculated, said magnesiumhydroxide solids comprising 50 to 60%, by weight, of the slurry; andphysically deflocculating the magnesium hydroxide solids in the slurryby subjecting said loose agglomerations of said magnesium hydroxidesolids to mechanical forces sufficient to break up said looseagglomerations of said magnesium hydroxide solids without substantiallychanging sizes of primary magnesium hydroxide particles to produce amagnesium hydroxide slurry having a chloride content of 0.30-0.42%, byweight on an MgO basis, that is stable such that any agglomeration andsettlement of magnesium hydroxide solids that occurs is resuspendableusing energy levels no greater than that produced by air sparging evenafter a period of 30 days from production.
 2. The method of claim 1further comprising adding a thickening agent to the deflocculated slurryin an amount of 1 to 100 ppm.
 3. The method of claim 2 wherein thethickening agent is selected from the group consisting ofcarboxymethylcellulose, xanthum gum and guar gum.
 4. The method of claim1 wherein said stabilized magnesium hydroxide slurry has a viscosity of50 to 1000 cps.
 5. The method of claim 1 wherein the density of saidstabilized magnesium hydroxide slurry is 1.4-1.6 g/cc.
 6. The method ofclaim 1 wherein said stable magnesium hydroxide slurry comprisessecondary particle agglomerates having a mean size in a range of about1.7-5.0 microns.
 7. A stable magnesium hydroxide slurry produced by theprocess of:providing a starting magnesium hydroxide slurry includingloose agglomerations of magnesium hydroxide solids, said slurry having achloride content of 0.30-0.42%, by weight on an MgO basis, and having aviscosity which enables substantially all of said loose agglomerationsof magnesium hydroxide solids in the slurry to be physicallydeflocculated, said magnesium hydroxide solids comprising 50 to 60%, byweight of the slurry; and physically deflocculating said looseagglomerations of magnesium hydroxide solids in the slurry usingmechanical forces sufficient to break up said loose agglomerations ofsaid magnesium hydroxide solids without substantially changing sizes ofprimary magnesium hydroxide particles to produce a magnesium hydroxideslurry having a chloride content of 0.30-0.42%, by weight on an MgObasis, that is stable, such that any agglomeration and settlement thatoccurs is resuspendable using energy levels no greater than thatproduced by air sparging even after a period of 30 days from production.8. The stable magnesium hydroxide slurry of claim 7 further comprisingadding a thickening agent to the deflocculated slurry in an amount of 1to 100 ppm.
 9. The stable magnesium hydroxide slurry of claim 8 whereinthe thickening agent is selected from the group consisting ofcarboxymethylcellulose, xanthum gum and guar gum.
 10. The stablemagnesium hydroxide slurry of claim 7 wherein said stabilized magnesiumhydroxide slurry has a viscosity of 50 to 1000 cps.
 11. The stablemagnesium hydroxide slurry of claim 7 wherein the density of saidstabilized magnesium hydroxide slurry is 1.4-1.6 g/cc.
 12. The stablemagnesium hydroxide slurry of claim 7 wherein said stable magnesiumhydroxide slurry comprises secondary particle agglomerates having a meansize in a range of about 1.7-5.0 microns.
 13. A stable magnesiumhydroxide slurry according to claim 7, wherein said stable magnesiumhydroxide slurry remains stable for up to 30 days without agitation. 14.A stable magnesium hydroxide slurry according to claim 7, wherein saidstable magnesium hydroxide slurry remains substantially free ofagglomerated solids for up to 30 days without agitation.
 15. A stablemagnesium hydroxide slurry comprising about 50 to 60%, by weight of theslurry, deflocculated magnesium hydroxide solids and a chloride contentof 0.30-0.42%, by weight on a MgO basis, said magnesium hydroxide solidsbeing suspended within the slurry such that any agglomeration andsettlement that occurs is resuspendable using energy levels no greaterthan that produced by air sparging even after a period of 30 days fromproduction.
 16. The stable magnesium hydroxide slurry of claim 15further comprising adding a thickening agent to the deflocculated slurryin an amount of 1 to 100 ppm.
 17. The stable magnesium hydroxide slurryof claim 16 wherein the thickening agent is selected from the groupconsisting of carboxymethylcellulose, xanthum gum and guar gum.
 18. Thestable magnesium hydroxide slurry of claim 15 wherein said stabilizedmagnesium hydroxide slurry has a viscosity of 50 to 1000 cps.
 19. Thestable magnesium hydroxide slurry of claim 15 wherein the density ofsaid stabilized magnesium hydroxide slurry is 1.4-1.6 g/cc.
 20. Thestable magnesium hydroxide slurry of claim 15 wherein said stablemagnesium hydroxide slurry comprises secondary particle agglomerateshaving a mean size in a range of about 1.7-5.0 microns.
 21. A stablemagnesium hydroxide slurry consisting essentially of about 50 to 60%, byweight of the slurry, deflocculated magnesium hydroxide solids and achloride content of about 0.30-0.42%, by weight on a MgO basis, saidmagnesium hydroxide solids being suspended within the slurry such thatany agglomeration and settlement that occurs is resuspendable usingenergy levels no greater than that produced by air sparging even after aperiod of 30 days from production.
 22. A stable magnesium hydroxideslurry comprising about 50 to 60%, by weight of the slurry,deflocculated magnesium hydroxide solids and a chloride content of about0.30-0.42%, by weight on a MgO basis, wherein said magnesium hydroxidesolids are suspended within the slurry without the use of stabilizingadditives such that any agglomeration and settlement that occurs isresuspendable using energy levels no greater than that produced by airsparging even after a period of 30 days from production.
 23. A stablemagnesium hydroxide slurry consisting essentially of 50 to 60%, byweight of the slurry, deflocculated magnesium hydroxide solids and achloride content of 0.30-0.42%, by weight on a MgO basis, said magnesiumhydroxide solids being suspended within the slurry such that anyagglomeration and settlement that occurs is resuspendable using energylevels no greater than that produced by air sparging even after a periodof 30 days from production.
 24. A stable magnesium hydroxide slurrycomprising 50 to 60%, by weight of the slurry, deflocculated magnesiumhydroxide solids and a chloride content of 0.30-0.42%, by weight on aMgO basis, wherein said magnesium hydroxide solids are suspended withinthe slurry without the use of additives such that any agglomeration andsettlement that occurs is resuspendable using energy levels no greaterthan that produced by air sparging even after a period of 30 days fromproduction.